In this work, we present the design of the nanostructured Lüneburg lens by using the electromagnetic field simulation and gradient optimization method that based on Transfor- mation Optics (TO) technique. In the proposed method, the nanostructured Lüneburg lens is simulated with an equivalent model, in which the original dielectric rods with varying size are transformed into uniform and fixed sized rods, with parameterized permittivity and permeability distributions, and then the nanostructured Lüneburg lens is optimized with the gradient opti- mization method. By using the TO modeling method, mesh refinement around the smaller rods can be avoided, and repetitions of regenerating the geometry and mesh grids during the opti- mization iterations can be eliminated, thus the computation efficiency is improved. The proposed design method opens up a new avenue to design and optimize a variety of photonic and optical devices with large number of complex structures.